Why do liquids have on linear and areal expansions?

A liquid occupies half of a vessel at a particular temperature. The volume of the unoccupied part remains constant at all temperatures. If alphaandgamma are the coefficients of linear and real expansions of a vessel and liquid, then gamma =

If alpha, beta , gamma are the coefficients of linear areal & volume expansions of solid then ( 2 alpha + 2 beta): (3 beta + 3 gamma) is

Why do solids have a definite volume ?

A non-conducting body floats in a liquid at 20^@C with 2/3 of its volume immersed in the liquid. when liquid temperature increased to 100^@c , 3/4 of body's volume 3. 4 is immersed in the liquid. Then the coefficient of real expansion of the liquid is (neglecting the expansion of container of the liquid)